Radio system



Oct. 20, 1931. t F. A. KOLSTER 1,828,705

RADIO SYS TEM Filed May 21, 1928 FIEJ. F"IE E- A TTORNE YS.

" 40 improvement over. theapparatus disclosed-in Patented Oct. 20, 1931 eRAPHeoMPAnY, or sansFRANoIsC camFoRN A;'*Ay Q T FORNIA haying both horizontally and}; vertically polarized 'compoiienQso that evn'though con "ditionsmay be unfavorable for the propaga tion of a wave polarized ini o'nef plane, the

component of the wavep'olarizeclfin another plane may be propagated "to successfully transmit the desired signal, Re'ferrrng,tothedrawmgs: F gurell is al Sld ,elevatlonal V1eW n cross jse tion illastr ating 'diag ta ifi y 1 131 P a s p r n e p ip'lsshfthisn .o i oocupledbyjthe singlefextended conductorinventions) V Figg2 isa front' fiew of the apparatus as shown in Fig. 1.

Fig.3 is a side eleyational yiefw', in cross section illustrating an:v apparatus f utilizing ,a rotatable antenna. o i

characteristics of apparatus suchasgsshown inFigs gl 'and 2. a F'gl 5is a: front Viewof; 'apparatus such as 1 shown in Fig. 3, with the antenna, means and signaling circuit shown diagrammatically; Fig.5 is a front'viewof apparatus'utilizin I both cross conductors forantenna means, an

a'rotatable antennm f My invention may be, outlined brieflyfas incorporated anoyel form of antenna and method of operating thesame. As tofcertain fe'atu1fes, the inventionhereinj disclosed is; an

t e c pen ing app i ion C Ki lstergand. Kruesi', No 27 95244; filed May 21,1928; In

that; application; there is disclosed aradio systernj utilizingia 'reflector having the approximate shapei of a 'paraholoi'd, "and "hay- -1cente r; ffWithsueh apparatus,if the antenna nieans s exc1ted w1th1rad 'o; current Qf'thCQirect wave length and m such rnanner as to st-secure propercurrent; maria-ma a true Rams SYSTEM object of the invention isto de}.

Fig. 4 is a curve illust ratingthefdirectional isa sl warm. a7'a24a R I bean1 of electromagnetic;radiation will he 7 pro ecjted from the reflector. The antenna means described in that'application is in the "form of an extended C7011dl lctor coupled 3 1 115 2 its ":IllGdlfil portion I to a; signaling: circuit. The conductor is formedso that the direction of current flow is substantially parallel i to the refleeting'surface', is symmetrical with respecttothe' axis of the refiectorand is at} k I ranged softhat', oscillatory currentsurges oc- ;cur back and forth laterally. with respect to lthe'jrefiector axis; 'With such an {arrangement; tho'the field isin the form-ofla true tion "ofthe antenna. conductor. For: example f lh conductor sjarranged in va ertical :p anat e planeof polarization is Vertical, l"

'while'i'f the plane of conductor isamngedgn ZoiitalQ Furthermore because otthe position within jthe'refie'ctor; the electromagnetic beam uproduced i's not uniforin; In otherwords" if the characteristics of such an apparatus employed v vfor; transmission were plotted for; different" planes coincident with the axis of propagation, the characteristic Icu'rve alongone plane, say the vertical" plane would notbe the same asgthe characteristic curve plotted; jalong another, plane, say thehorizontaL,

v In this invention I utilizeia concentrated field of radiationjin the form of a truebeam which includes both vertically"andvhoriaon an polarized components. Furthermore the fieldis more uniform' thanthat ofthe pendin application. To obtain these results there is utilized in accordance with this in: f

yentiomatthe transmitting. station'end, an 5 n enn radiator ,Which' extends in two di inensfionsrather than along 'ajsingle dimen- 0 o-'f. i pr fe d: to armn'gel hi radifflnFigsql andQof the drawings l a i V i "to thejapparatus"disclosed ia'th fjabove co- FREDERICK A. KOLSTEROFiPliLOiALTO,"CALIFORNIA: assienon ro V-FEDERAL mam-- fappa'ratus disclosed" in the above notedi-fcjoendin a lication. This a) aratus consists of a reflector 11 in the form of a surface of complete revolution which has at least an approximate focal center.. For optimum operation it is desirable to employ a reflector which approximates a true paraboloid. The refiector may be formed of any highly conductive material, such as coppersheathing or copper mesh. The focal center of this reflector hassjbeenindicated at 12,.at which point there is arranged theantennameans 13 which is employed to absorb or radiate radlo energy. As explained above, the .con-

' ducting material forming the antenna means fo'f 'conductorsil' and 15. In Fig. 2v there is or supplied bythe signaling circuit 16 preferlength o-f' th'e paraboltiid 11'. found that best results can be obtained if this wavel'en th is equal to four times the shown onlytwo conductors 14 and 15 which arearranged at right anglesto each other. Two conductor-shave given good results and provide asimple structure, although'itis obvious thatimorefthan two conductorsfmay be employed. I

The wave length of energy to be received ablybear's a definite relationshipto the focal It has been focal length. ow'ever't'he focal length may be any odd multiple of the quarter wavelength. For example if the focal length is 'one meter, best results can beobtained by operating the signaling circuit 16' upon four .meters. However a wave length of 1 meters may'also be employed. In any event the wave length should not materially exiceedjfourtimes the focal length. In order 1 tance between: conductors 14. and 15 and the reflecting surface 11, it is preferred to bend conductors 145 and 15 so that-they fall within 'the' surface of a paraboloid similar to the to reduce and "better distribute the capaci- Ireflector 1 1 and having its axis coincident therewith. This arrangement is shown in Fig; 1,,in which conductor 14; has been shown in a vertical position and conductor 15 horizontal. e

Assuming that the apparatus is employed fortransmission purposes, when high frequency energy of'proper wave length 1s appliedto the conductorsl and 15-from signalmg c rcuit 1.6,fa truebeam of radiation, will ected from-the paraboloidrefiector 11.

and the reflector .axis.

A typical characteristic curve for this beam is shown in Fig. 4. Horizontal axis 19 represents the direction of maximum radiation while the point 20 represents the source of radiation, which in this case is the opening of the reflector. Curve 21 represents in polar coordinates the characteristics of the apparatus substantially as shown in Figs. 1 and 2, and was plotted from field strength measurements made at various points equidistant fromthe reflector- The distance measured along a straight line from the origin'QO to any point on curve 21, represents the relative quantity of energy radiated in the direction of that line.

An analysis of the characteristics of a transmitting system utilizing the above apparatus, shows that the radiation throughout across section of the radiated beam is fairly uniform. If single linear conductor is employed for a receiver, and this cong ductor is arranged so that it extends substantially at right angles to the direction of received radiation thenas the receiving end is turned about such axis, the intensity of received signals will'vary a certain amount but will not reduce to zero for any position.

In other words the beam of radiation consists 'of both horizontally and vertically polarized components'and these components can 'conjointly affect a receiving antenna,

provided of course that the antenna at the receiv ng station is capable ofreceiv ng'both horizontal and vertical components; Such a receiver may be had by utilizing apparatus substantially the same as that shown in Figs. l and 2, that is, apparatus making use of antenna means having conductive material, extending in twodimensions.

It isbelieved that a beam of radiation such as is projected from apparatus such as described is more effective for radio signaling than are radio waves polarized in only one direction. Under certain conditions of transmission, one component may not carry through'to the receiving station, but in'such case the probabilities are that the other component will'carry thru to aifect the receiver.

In Figs. 3, 5 and 6 there is shown other apparatus capableof being operated in such a manner as to, secure more uniform transmission between two stations. In this case the antenna means placedwithinthe paraboloidal reflector 11 is bodily rotated about the'axis of the'refiector. Thus as indicated diagrammatically in Fig. 5, a simple antenna conductor 22 is arranged 'nearthe focal center of the reflector and is coupled to a signaling circuit'16:. Suitable means is. provided for bodily spinning it about the focal center Vvith such an arrangement it isapparent that at 'any one instant, thefradiation field. will be polarized in one plane,jdepending uponthe position of the conductor 22, but asthis conductor-is rotating, the plane of polarization likewise;

rotates. The conductor 22 is preferably rotated sufficiently fast to-change the plane of is at least musical.

polarization at a fre'quencywhich is at least" high enough-to be musical. Assuming that.

such an appartus' is employed with a receiving antenna polarized chiefly in one plane,

the energy received the ant'enna varies according to the rotation of conductor 22, and

if this rotation is at a sufficient rate,'the re- The receivingv antenna can also be rotated about an axis substantially parallel to the direction, of propagation of received radiahas been refracted or reflected to a substanantenna at the receiving end. p of polarizationisfrequently changed. Such i i v polarity changes may cause fading effects and no changes in the strength of received signals in response to changes in the plane of polar- V tion. Where the receiving antenna is ro' tated at the same rate as the transmitting antenna conductor, no modulation efl'ectis pro duced, butwhen the receivingantenna is ro-Q,

tated at a. rate of rotation other than that ofthe transmitting antenna, received en-V ergyis modulated at a frequency. determined by the algebraic difference, between the rates of rotation.

In addition to making possible a system of modulation, rotating .the antenna means makes possible more uniform transmission under condltions in which waves polarizedln one plane may be attenuated to a greater extent than waves polarized in other planes It has been previously determined by other investigators thatwhen received radio energy tial degree by the I-Ieavyside layer, its plane non-uniform reception. 2 In the case Where the plane of polarization of the transmitted beam is continually changed there should be ization caused by the Heavyside layer. The apparatus described with reference to Figs. 3, 5 and 6, can therefore be. used to advantage in systems in which the field of radiationis directed upwardly toward the Heavyside layer.

In Fig. 3 there is illustrated a practical apparatus such as. indicated diagrammati-- cally in Fig. 5. In this case the antenna conductor 22 is formed with an inductancel23 in its intermediate portion. Conductor 22 is mounted upon a spindle 24, and suitable means such as abelt 26 is provided for eflecting rotation of spindle 245 and antenna conductor 22. Inductance 23 is preferably ar-l ranged concentric with-the axis of rotation, and is coupled to a suitable "signaling circuit as by means of another inductance 27 In this particularinstance conductor 27 has been,

' shown as connected to transmitting oscill'ator located for example within a housing;

apparatus at the receiving end. When rota tionof the antenna meansat the transmitting As has previously specified, the 'medial portion of conductor 22 isapproxi- .mately at the focal center of-the reflector 1 1.

1 and 2. As has been previously explained when utilizing suchcrossed antenna, conduc-- tors,the beam of radiation at any one instant i i i is more uniform. Furthermoreat any one instant the polarization is in two dimensions, depending upon the. directions of conductors 31 and 32.; VVhile the arrangement of Fig.2 secures a more uniform beam of radiation than is possible by utilizing a single antenna conductor, the arrangement of Fig.6 carries such uniformity to a greater degree The apparatus described above is particu larly effective for securing beam transmission of radio waves. It is apparent that when it is employed for transmission purposes, ordi-' naryforms of antennas may be employed at the receiving end. However in order to obtain the greatest benefit from the direca:

tion'al characteristics of'the system, it is pre- I ferred to employ similar highly directive end is resorted'to, the antenna conductor at the receiving end can be stationary or can lso be rotated to secure certain special effects; 2' .Furthermore it is possible .to transmlt without a rotating antenna, and to use a rotating I claim: I

j'In a radiosystem, a reflector approximating a parabolold and formed of conducting material, antenna means disposed near the. focal center. of the reflector, andmeans for rotating said antenna means. v Q g In testimony whereof,'I have hereunto set my hand.

, r 1 e 11o i FREDERICK, A. KOLSTEB. j 

